186 JOURNAL OF THE ARNOLD ARBORETUM [VOL. in 



on Centre Street, and on Bussey Street at the eastern base of Peter's Hill, 

 and are valuable in showing several important New England trees in their 

 adult state. 



ARRANGEMENT OF THE LIVING PLANTS 



The trees which have been planted are arranged in botanical sequence 

 in family groups, the genera of each family and the species of each genus 

 being placed together, the arrangement beginning with the Magnolia 

 Family at the Jamaica Plain Gate and ending with the Pinaceae at the 

 Walter Street Gate. 



That they may show their habit under different conditions several 

 individuals of important North American species have been planted close 

 together in groups, and at a distance from the group an individual of 

 the species is planted with sufficient space about it to insure a full develop- 

 ment of branches. A representative of almost every genus stands near a 

 drive so that visitors passing along the Arboretum roads and gravel paths 

 can obtain an idea of the genera of trees hardy in Massachusetts and of 

 their relation to each other. An attempt has been made to place the 

 Family groups in positions where the trees may find favorable conditions 

 for growth without interfering with the beauty of hills and valleys, and 

 of the natural woods. Access to the different groups of all the trees is 

 secured by grass-covered paths several miles in length which reach every 

 part of the Arboretum and make easy the examination of the trees. 

 Hardy shrubs of genera in which there are not species which are trees are 

 arranged in the same sequence as the trees in parallel beds ten feet wide 

 with a total length of 7765 feet, and separated by grass-covered paths. 

 This shrub collection is situated on the level ground near the Forest Hills 

 entrance and is surrounded by a trellis on which are grown vines and other 

 climbing plants. It has been established for the instruction of gardeners, 

 landscape gardeners and others interested in shrubs who can find in it all 

 the perfectly hardy species of many genera conveniently arranged for com- 

 parative study. Insufficient space in the area devoted to this shrub col- 

 lection has made it necessary to arrange the shrubs belonging to genera 

 in which some of the species are trees in groups as near as possible to the 

 trees of the same genus or Family; as, for example, the Spindle-trees 

 (Evonymus) and the Sumachs (Rhus) on opposite sides of the Meadow 

 Road, the Lilacs below the Ash-trees on the left hand side of the Bussey 

 Road, the Viburnums near the junction of the Bussey and Valley Roads, 

 and the Kalmias and Rhododendrons at the base of Hemlock Hill. Large 

 numbers of shrubs have also been planted to form margins to the roads 

 and an undergrowth among the groups of trees, native shrubs having been 

 chiefly used for this purpose in order to preserve as far as possible a New 

 England character. Peter's Hill has been used for an extension of the 

 Pinetum, for the principal collection of Hawthorns which occupies its 

 eastern slope, for a large supplementary collection of Crabapples and species 



